This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A234286 #12 Nov 08 2014 08:03:03 %S A234286 3,9,13,15,17,21,23,27,29,31,33,35,39,43,45,49 %N A234286 Positive odd numbers n such that 2m - sigma(m) is never equal to n, where sigma(.) is the sum of divisors function A000203. Conjectural. %C A234286 The terms shown here are conjectural, based on a search up to 10^20 made by Davis et al. (2013). %H A234286 Nichole Davis, Dominic Klyve and Nicole Kraght, <a href="http://dx.doi.org/10.2140/involve.2013.6.493">On the difference between an integer and the sum of its proper divisors</a>, Involve, Vol. 6 (2013), No. 4, 493-504; DOI: 10.2140/involve.2013.6.493 %Y A234286 Cf. A000203, A033879 (2n - sigma(n)). %Y A234286 For negative values of n see A234285. %K A234286 nonn,more,hard %O A234286 1,1 %A A234286 _N. J. A. Sloane_, Dec 28 2013